The Australian Sports Anti-Doping Authority is remaining tight-lipped amid reports it is about to take action against 57 top-line footballers from two major codes.

As ASADA's new chairman begins work on Monday, the organisation is ready to issue show-cause letters imminently, according to a Fairfax Media report.

The report says ASADA, investigating use of banned substances in two football codes, could issue show-cause notices to 40 players from AFL club Essendon in 2012 and 17 players from NRL club Cronulla in 2011.

ASADA refused to comment on the report.

"ASADA is unable to discuss operational matters associated with an investigation until such time as its legislation permits," an ASADA spokesman said.

The AFL said it was unaware of any developments in ASADA's investigations.

"We haven't been provided with any update from ASADA and the investigation remains in their hands," an AFL spokesman said.

ASADA has been investigating possible use of banned substances at Essendon in 2012 and at Cronulla in 2011.

Fairfax Media reported up to 40 players at Essendon in 2012 at the time of the AFL club's controversial supplements program would receive show-cause notices, with 17 players on Cronulla's NRL roster in 2011 to also be issued the notices.

The use of banned substances carries a mandatory two-year ban and while some players have moved on, both football clubs face decimated playing ranks if players are ultimately found to have transgressed anti-doping laws.